I thought I would post my setup and the dyno numbers I got today. I also need opinions on how I can pick up another 40hp. Here are the specs:

'92 Camaro RS/SS
New GM 350 LO5 truck block with ZZ4 internals & 9.8:1 comp.
Edelbrock 6085 Performer heads as delivered
GM LT4 1.6 roller rockers
Crane roller cam: 208/214 467/482 112 (lift is with 1.6 roller rockers)
Edelbrock TPI base - gasket matched only
SLP siamesed runners - gasket matched and opened up a bit
Plenum - ported & siamesed to match runner gaskets
Large/big tube runner gaskets - siamesed at plenum
52MM TB
New style Accel 24# injectors set to 45psi @ WOT
Timing set at 10* BTDC
Ed Wright custom chip
SLP 1-5/8" headers, 3" cat & 3" catback exhaust
700R4 with TransGo kit and 5,200 rpm shift points
3.5" aluminum driveshaft
3.42 gear with 275/40/17 tires

Dyno results:

SAE/rear wheel power: 258.5 @ 4,700rpm
SAE/rear wheel torque: 339.4 @ 3,700rpm

Corrected power: 310.2 using 20% loss
Corrected torque: 407.3 using 20% loss

This was in Chicago (close to sea level?)
Baro pressure = 29.22hg
Vapor pressure = 0.32hg
Intake air temp = 85.5*
Air/fuel ratio average at WOT = 11.8

I'm quite happy with the numbers. I know there is more torque than listed because the 2 dyno tests started at 3700rpm and it was already the "peak" torque number for both runs. The A/F ratio is on the rich side at WOT. I plan on having Ed Wright lean it out some based on the dyno sheet specs. The HP curve is very flat with at least 240hp from 3700 on up to 5100rpm. Again, the dyno started at 3700rpm, so I don't know what the numbers look like below that.

I'd like some suggestions on how to gain about 40hp. I know the cam is the first place to start, but I'll need solid info. I'd also like to keep the current intake setup if possible. Any other comments or suggestions regarding my setup? I'd appreciate it

 

Damn, all those mods and you still didn't touch a stock LS1's #s. If I were you I would probably drop in a cam with at least .480-.500 lift, at least 214* of duration on both sides and hog out those Performer heads a lil bit cuz if I am correct the stock L31 Vortech heads flow better #s than those. You would take full advantage of your intake setup with these mods being that your siamesed runners and plenum like the higher RPMs. You probably want a 2500 stall or something in that range and higher shift points with these mods.

 

Just for comparison, mine pulled 287 hp and 367 lb/ft with TPI and 306 hp 335 lb/ft with a Holley Stealth Ram. It's in the link in my sig.

 

GO for like a 230 @ .50 duration, and ya, do some porting to those heads, but You probably don't want to rip into your motor again. Your numbers are still gonna make your car move pretty good man! ANd its true the stock vortecs do out flow those heads, and it been said the vortecs have a better combustion chamber. But hey the performer heads are still kick ***.

 

Depends what your end goal is, and budget.

For example, Kevin91Z has run 12.8 and has dynoed around 320 rwhp and giagantic torque. LTR combo with L98 heads and LT4 hot cam. To get to something like this you'd want to pull those heads and port 'em up a little and swap a real bumpstick in there. And if you port teh SLPs up real nice you coud keep them.

Or you could always swap to a short runner intake like the stealth ram or LT1. And a real cam.

Some PROM tuning woulodn't be a bad idea either.

 

Since the chip program is on the rich side, would I need to have it "retuned" if I slip in a hotter (real...thanks ED!) cam? I would think that with the extra duration & lift, that program might be just what I need...

FYI: I have a 2500 stall convertor already.

I plan on going back to the dyno in a few days and I'd like to do some simple on the car tuning to see if I can get more power out of it. Any suggestions on fuel pressure setting and timing? More/less pressure means what? More/less timing means what?

Anything else I can do to squeeze at least another 5-10hp out of the current setup until I change the cam? Thanks!

 

If it were me, I'd port the crap out of the heads and get the LPE 211/219 cam. GM High Tech Perf. magazine had a writeup about ported Edelbrock heads, LPE 211/219 cam and LTR TPI. The author said he has used this combo a number of times and gotten C4 Vettes running low 12's with it.

 

the heads arent the best in the world, but they do beat stockers. you are pig rich, run for a 13.x depending on what your car likes best and you should see a good hp increase. swapping to a better flowing intake like the stealth ram or miniram would boost hp numbers alot, tpi just doesnt do much for the hp numbers.

 

Thanks for the tips, Guys.

I still need to know how to lean out the engine without reprogramming the chip...My fuel pressure is at 45psi with 24# injectors. Will higher or lower pressure help at all?

 

Well if you want to try and lean it out a little, then lower the fuel pressure some. A decrease of 4 psi fuel pressure will lower the injector flow about 1 lb/hr. Also, try advancing the timing a couple of degrees. I know on my car that 4* timiing makes a huge difference in performance.

 

wait a minute, he has a world of mods compared to where i am at and only picked up 50hp over my nearly stock numbers.

i have 100K+ miles with slp runners, ported plenum, flowmaster 80, k&n's and an airfoil and got 206hp at the wheels with 300 lbft. i know he has more then 337 lbft since i peaked at 3100, but all that cash and mods to get 50hp and 500 rpm seems a little wrong doesnt it.

the idea makes me want to cry.

 

You're comparing dyno numbers from different dynos. Big mistake. A dyno is a tool for comparison of the same car on the same dyno. And he gained 50 rwhp which is more than that at the flywheel. And, that's not a huge cam by any stretch. I'd say that's the biggest factor in his perceived low numbers.

 

true no 2 dyno's are the same but i have also seen stock numbers on here around 225hp for several people. his dyno must suck and theirs must be really great then?!

 

I know the cam is robbing me of some power. Also, the air/fuel ratio of 11.8:1 (rich) is not helping me either. I will have "revised" dyno numbers later this week after some tuning....remember, this was the first dyno run after the engine was built. I know there is more power in there somewhere! But I do like the massive torque I'm seeing so far I'm sure there is more torque under 3700rpm, so we'll see. But I'm not ashamed of having 400lbs of torque up at 3700rpm, either!

Do be honest, I expected around 285rwhp, so I'm looking for that extra power now!

As far as stock TPI with 225rwhp...I doubt that! That equates to about 270hp on an engine that was rated at 245hp from the factory. No way that is possible.

Look for the revised dyno numbers from the same dyno later this week! Thanks for the comments, Guys...

One more thing: I should mention that this entire setup replaced a 305 LO3 TBI engine rated at 170hp & 255tq from the factory. All of the parts listed were part of a complete buildup, with torque being my original goal...So, I picked up 140hp & 152ft/lbs from the original setup. Now that's not too bad is it

 

if you do a search you will find the number i was talking about. ok not bone stock but pretty close with stock runners and all, mostly listing ignition mods. i know i was shocked, i thought my 206.7hp was pretty dang good, still do really!

if you can get a pull started below 3000 you will find all your tq down there. my pull started about 2600 and peaked tq about 3100, my hp peaked allot lower then 4700 though so at least you got some rpm. for your investment i would have to say shooting for 285hp is about what i would want.

 

Scott C, you claimed that your air/fuel ratio was rich at 11.8:1 at WOT. But if the information I read is correct, the stock Tuned Port computer commands 11.5:1 at WOT while 14.7:1 is maintained only at part throttle acceleration.

 

The air fuel ratio the ECM commands is based off of the cars oxygen sensor which is not accurate. Comparing the wideband O2 readings that a dyno gives to the stock O2 sensor readings is like comparing apples to oranges. The idea would be to get the car dialed in on the dyno. Then once its tweaked just right, look and see what the O2 readings are from the computer. Then in the future just from looking at scan tool O2 voltage readings, he would have a good reference point to know whether the car is going out of tune.

 

I would say that your cam is the biggest bottleneck in the system. I have the same block & heads as you, but still have a completely stock TPI on top. And with the hot cam and I dynoed 12 hp and 15 tq more than you. If I had an aftermarket LTR setup on top, I would expect closer to 300 rwhp.

Also, did Ed Wright adjust your chip to accomodate the 10* base timing? Cause the stock setting is 6*, and the ECM adjusts the timing of the engine on the assumption that the timing is set to 6*. By having it set at 10*, you're basically adding 4* of timing at every single point on the curve.

 

I actually did several test runs with my Diacom program today just to see more details. I captured data for 3 separate full-throttle runs and for all 3 runs at WOT, the air/fuel ratio was between 10.8 and 11.2.

The 2 dyno runs were between 11.2 and 11.9. This looks to me like I am running "Pig Rich" as someone else said. My O2 volts are all in the low-mid 900's at WOT with the mixture reading of "RICH" throughout the entire rpm range.

Part throttle seems to be programmed correctly from what I can see. It spends equal time between rich & lean at 25-50% throttle.

I already called Ed Wright and I'll be sending in the chip for a new program. I will have dyno numbers by next week to compare with the baseline numbers I got this week. Please stay tuned...

 

just some friendly input for everyone who hasn't visited the DIY PROM board yet

(1) at WOT, the stock O2 sensor isn't used - it's just along for the ride. The computer simply sprays the amount of fuel the stuff inside the computer/PROM tells it to spray. In no way does the O2 sensor affect any of that part at WOT. Try this, Go to the drag strip. Unplug O2 sensor, run the 1/4, and then look at the diacom data. It's still reporting the A/F ratio - it's only a calculated ratio not a measured value.

(2) The O2's voltage can not be used to gauge A/F ratio. All narrow band O2 sensors go to around 900mV (0.9V) when 'rich'. For a narrow band sensor, 'rich' is defined as anything lower than 14.7:1. So a reading of 900mV can indicate 14.0:1, 13.0:1, 12.0:1, .... there is no way to know.

(3) Part throttle will almost always spend equal time between rich and lean, this is the essence of a switching O2 sensor. Provided that your BLM values are roughly around 128 at part throttle, then your VE (Volumetric efficiency) table is in good shape, and this is important.

I for one am pretty impressed with your dyno numbers for a LTR setup. The SLP "siamese" runners aren't very "siamese", but a grinder fixes that. I bet with nothing more than making the runners more siamese and maybe a bit more cam (LPE 219, LT4 HOT cam, something like that) you'll see another nice jump in power. Give a look into burning your own chip too. Obviously you are doing pretty good right now so it's not immediately important, but if you start now, then you'll be ready in a few months when you bolt on a miniram/LT1/stealth ram

Keep the info comin', i'm interested in seeing the next dyno tests.

 

Thanks for the O2 info! That helped me understand things a bit better. BUT, what about the wide band readings from the Dynojet? They indicated 11.3-12.0 air fuel ratio at WOT. Doesn't that indicate that I'm running rich? The guy that ran the dyno said I'm rich and I should gain some power by leaning it out some. We'll see!

On a very interesting side note, I compared my numbers to a car with same engine & TPI setup from the same dyno and guess what? We were within 3rwhp of each other!! I think I have a bit more torque, but power was almost identical! I'm at least pleased with that comparison which tells me I'm right on target so far.

 

Yes, you can trust the wideband O2 readings from the dynojet, and 11.3 - 12.0 is relatively rich (but about in the range where GM calibrates them). That's why everyone says the stock TPI calibrations are rich (because they are!). But that keeps warranty concerns down.

Since you're having Ed do your chips right now, just forward him the dyno WBO2 readings and your diacom scan data and tell him to lean out WOT by about 8% or so and correct anything else he can correct based on your data. With the proper DIY equipment you could also do this yourself in a few minutes time. Keep in mind there is no "magic" AFR you are trying to hit, you just have to give the engine whatever it needs to make the most HP.